Syntax

Ghost's syntax pulls a lot of influence from other C-like languages. In particular Go, JavaScript, and PHP. It's designed to be familiar to those coming from these languages, with the aim to be simple and predictable.

Scripts are stored in plain text files with a .ghost file extension. Ghost does not compile ahead of time: programs are run directly from source, from top to bottom like any other scripting language.

Comments

Single line comments start with // and continue to the end of the line.

// This is a single line comment

Block comments are enclosed within /* ... */ and can span as many lines as necessary.

/*
This is a block comment.
*/

Comments behave like whitespace and are discarded during execution. While single line comments are the norm, block comments are useful within an expression or to disable large swaths of code.

Reserved Words

Ghost has a small subset of reserved words used as predefined identifiers. None of the identifiers listed here should be used as identifiers in any of your scripts.

function true false if else return while and or

Identifiers

Naming rules are similar to other programming languages. Identifiers must start with a letter or underscore and may then contain letters, digits, and underscores. Case is sensitive.

hello
camelCase
PascalCase
_under_score
abc123
ALL_CAPS

Blocks

Ghost uses curly braces to define blocks. You can use a block anywhere a statement is allowed, like in control flow statements.

pressure = 3.6

if (pressure > 3.4) {
  print("Pressure is above critical levels.")
}